1974 Dart 318 crank, but no start (Solved)
Telling me it's so bad I should rip it out and start over isn't saying anything bad to, or about me? Okay boomer. You didn't offer any help to my post, only bashed it. I'm sure all of your cars were show cars all the way thru the building phases, right?
Ok, I'll give you a wall of helpful text you.
Assuming you wired everything correctly.
And you have a 4 pin ECU/ICM.
Tools you need are:
A non LED test light
A multimeter
Key in run, you should have full-ish battery voltage at one end of the properly used ballast resistor and reduced voltage like 6 or so volts at the other end that has the wire that goes the coil. If no voltage at all, check your wiring or ignition switch circuit.
key in run, if you have full battery voltage at one end of the ballast resistor and no voltage at all at the other end, you need a new ballast resistor. If you put a jumper lead across both sides of the single ballast resistor or 12 volt power to the coil feed of the dual resistor, you should be able to now energize the coil.
Key in start, you should now have full battery voltage at the other end of the ballast resistor that has the lead that goes to the coil, because there is another lead that spliced in that supplies full battery voltage when cranking. If no voltage, check you wiring and ignition switch circuit. (I am aware that on certain vehicles it my get power from the starter relay)
Ok, let's say things look good at the ballast resistor so far. Let's move on to the ignition coil.
Key in run, you should have 6 or so volts at the positive end of of the coil. If not, check the wiring.
Key in start, you should have full battery voltage at the positive end of the coil. If not check the the circuit, maybe with a test light, I've encountered wires just good enough to show voltage, but fail under load.
All looks good so far? Moving on then.
Key in run, check the voltage on the negative side of the coil. If you get full battery voltage, suspect an open circuit in the wiring, a bad ECU or ECU ground.
Using a test light on the negative side of the coil, key in start with the engine cranking, the test light should flash. If it does flash and you still have no spark coming directly from the coil, you have a bad coil. If the test light does not flash, you may have an issue with the ECU, distributor pickup, or the circuit for the distributor pickup that goes the the ECU.
Now let's get into the distributor pickup.
As each tooth of the reluctor passes by the pickup a voltage signal is generated and picked up by the ICM/ECU which will break and complete the connection of the negative side of the ignition coil. You can use a scope to check the pickup, but most of us may not have a scope, so a normal multimeter will do fine. With the multimeter on the AC voltage setting and the two multimeter leads in the two connections from the pickup and the engine cranking you should a very low voltage reading, like around .2vac or close. If you see nothing, it's most likely nfg (of course you should also check the reluctor to pickup gap if you messed with that).
Other things to check:
Voltage to power the ECU/ICM is there at the connector.
Pickup signal at the ECU connector.
Wiggle check wires.
Coil to distributor and Spark plug wires.
Cap and rotor.
I hope that is helpful enough for you. I don't know the color of your wires, so that is for you to figure out.
Mic drop!